avra-cadavra/clean-architecture-implementation

Clean Architecture Implementation

Layer Structure

lib/
├── core/          # Core business logic, models, services
├── data/          # Data sources, repositories (implementation)
├── domain/        # Use cases, repository interfaces
└── presentation/  # UI, BLoCs, widgets, pages

Layer Responsibilities

Core (lib/core/)

• Business logic
• Models (entities)
• Services
• Common utilities
• No framework dependencies (as much as possible)

Domain (lib/domain/)

• Use cases (business logic workflows)
• Repository interfaces (abstract)
• Domain models/interfaces
• No implementation details
• Framework-independent

Data (lib/data/)

• Repository implementations
• Data sources (local/remote)
• Data models (DTOs)
• Framework-specific (GetStorage, Drift, HTTP, etc.)

Presentation (lib/presentation/)

• UI components (widgets, pages)
• BLoCs (state management)
• Controllers
• Flutter-specific code

Dependency Direction

Dependencies flow inward:

• Presentation → Domain ← Data
• Presentation → Core
• Data → Domain
• Domain → Core
• Core has no dependencies on other layers

Presentation → Domain ← Data
     ↓           ↓
    Core ←──────┘

Examples

✅ GOOD: Correct Dependency Direction

// Domain (abstract interface)
abstract class SpotsRepository {
  Future<List<Spot>> getSpots();
}

// Data (implements domain interface)
class SpotsRepositoryImpl implements SpotsRepository {
  final SpotsRemoteDataSource remoteDataSource;
  final SpotsLocalDataSource localDataSource;
  
  // Implementation
}

// Domain (use case uses repository interface)
class GetSpotsUseCase {
  final SpotsRepository repository;
  
  Future<List<Spot>> call() => repository.getSpots();
}

// Presentation (uses use case)
class SpotsBloc extends Bloc<SpotsEvent, SpotsState> {
  final GetSpotsUseCase getSpotsUseCase;
  
  // Uses use case
}

❌ BAD: Wrong Dependency Direction

// Domain depending on data (WRONG)
import 'package:avrai/data/models/spot_model.dart'; // ❌

// Presentation depending on data (WRONG)
import 'package:avrai/data/repositories/spots_repository_impl.dart'; // ❌

File Organization

✅ GOOD: Layer-Based Organization

lib/
├── core/
│   ├── models/
│   │   └── spot.dart
│   └── services/
│       └── spot_service.dart
├── domain/
│   ├── repositories/
│   │   └── spots_repository.dart
│   └── usecases/
│       └── get_spots_usecase.dart
├── data/
│   ├── datasources/
│   │   └── spots_remote_datasource.dart
│   └── repositories/
│       └── spots_repository_impl.dart
└── presentation/
    ├── pages/
    │   └── spots_page.dart
    └── blocs/
        └── spots_bloc.dart

Service Patterns

Core Services

Core services belong in lib/core/services/:

// lib/core/services/my_service.dart
class MyService {
  // Business logic
  // No Flutter dependencies
}

Domain Use Cases

Use cases belong in lib/domain/usecases/:

// lib/domain/usecases/get_data_usecase.dart
class GetDataUseCase {
  final RepositoryInterface repository;
  
  Future<Data> call() {
    // Orchestrates business logic
  }
}

Testing by Layer

test/
├── unit/
│   ├── models/          # Domain entities
│   ├── repositories/    # Data layer
│   ├── usecases/        # Business logic
│   ├── blocs/          # State management
│   └── services/       # Core services
├── integration/        # Cross-layer
└── widget/            # Presentation layer

Reference

See existing architecture in:

• lib/core/ - Core layer examples
• lib/domain/ - Domain layer examples
• lib/data/ - Data layer examples
• lib/presentation/ - Presentation layer examples